1. Field of the Invention
The present invention relates to a decorative light blinking device which blinks in response to a change in a sound, such as a low-frequency sound of, e.g., a drum, a high-frequency sound of, e.g., cymbals, or a singing voice of all frequency components contained in music being played or broadcast. This light blinking device may be suitably installed in a place, such as a so-called "karaoke (do-it-yourself vocals) bar".
2. Description of the Related Art
In places where music can be heard, such as discotheques and karaoke bars, when visual effects are used to help create the atmosphere of the place, means have hitherto been employed in which illuminants emit light in response to music so as to create an atmosphere which appeals to the human eye and ear.
There has heretofore been a device which is operated through computer programs which are written beforehand in accordance with music, and another device which blinks illuminants in response to the dynamics or high and low frequencies of a sound. Such well-known devices are employed when illuminants are appropriately blinked in response to various types of music, such as one in which the sounds of a drum and cymbals and bass and soprano voices are intermixed. The former device operating through programs is capable of very precisely blinking illuminants in response to music which has already been programmed. Such a device, however, is not capable of immediately coping with music which has not yet been programmed, and thus it lacks versatility. In addition, the device is not suitable for general use because it is expensive, and is therefore only suitable for business use in limited types of places.
The above device for blinking illuminants in response to the dynamics of a sound is a device which responds to a sound to blink illuminants regardless of the type of sound, for example, whether it is the sound of a drum or symbols, as long as the pressure of the sound is the same. When the sound pressure of music happens to be increased at the climax of the music, such a device may be operated so as to keep the illuminants turned on, and is thus insufficient for visual effect purposes.
As opposed to the above device, there is a device for blinking illuminants in response to the frequency of a sound. This device does not have the above problem of the former device, and thus it is versatile and effective in producing visual effects. Such a device will be described below.
FIG. 3 is a block diagram showing the functions of a conventional device for blinking illuminants in response to the frequency of a sound. Referring to FIG. 3, reference character 20L denotes a low-pass filer; 21, amplifiers; 22, detecting circuits; 23, time constant circuits; 24, voltage comparators; 25, reference voltage applied to the voltage comparators 24; 26, output circuits; and 27, illuminants. The low-pass filter 20L, the amplifier 21, the detecting circuit 22, the time constant circuit 23, the voltage comparator 24, the output circuit 26, and the illuminant 27 constitute a one-channel functional block corresponding to a low frequency of sound. In FIG. 3, reference character 20B denotes a bandpass filter; 20B', another bandpass filter having the same circuit structure as that of the bandpass filter 20B and a frequency band different from that of the bandpass filter 20B; and 20H, a high-pass filter. Such a one-channel functional block, which is a light blinking block, is attached to the back of each of the filters. The number of filters corresponds to the number of frequencies. In FIG. 3, like numerals denote the same components in the same functional blocks. Symbol In denotes a point at which an electric music signal is input.
When the electric music signal is input from equipment, such as audio equipment Ad, to the input point In, it is first transmitted to the low-pass filter 20L, the high-pass filter 20H, and bandpass filters 20B and 20B' having the different pass bands, and then classified according to a frequency set in each filter. By this time, since the music signal has been attenuated by an AC resistant component, which is an LCR constituting each filter, the amplifiers 21, connected to the filters 20L 20B, 20B' and 20H, amplify the signal. The output of each amplifier 21 is passed through each detecting circuit 22 to convert it into a DC component, which in turn is converted by each time constant circuit 23 into a voltage level of a direct current.
Voltage outputs from the time constant circuits 23 increase as the frequencies of the electric music signal input through the input point In approach the center frequencies set in the filters 20L, 20B, 20B' and 20H. In other words, when a frequency of all frequencies contained in music is close to the center frequency of each filter, the level of the voltage output from each time constant circuit 23 increases.
The voltage output from each time constant circuit 23 is input to each voltage comparator 24 to compare it with the reference voltage 25. If the output voltage exceeds the reference voltage 25, the output circuit 26 corresponding to the output voltage is operated to blink the corresponding illuminant 27.
As described previously, when the center frequencies of the filters are set to the frequency bands of the sound of a drum and cymbals, the above device blinks illuminants in accordance with such frequency bands. However, the filters used in the device are of a general-purpose type and have approximately -6 dB/oct. Therefore, an audio frequency range (from about 20 Hz to 20 KHz) can be divided into three bands at most when illuminants are reliably blinked on and off. The number of frequency bands into which the audio frequency range is divided is equal to the number of illuminants blinking on and off. The illuminants do not blink precisely and synchronously in response to the dynamics of the sound of music.
Even if a device overcomes the above problem, filters, each having approximately -18 dB/oct., would have to be utilized because the extent to which amplifiers can amplify the signal and the accuracy with which voltage comparators can operate are limited. In addition, the circuitry in such a device is complicated. The above audio frequency range can be divided into five bands at most. For this reason, such a device is ineffective in producing visual effects and operates to blink illuminants on and off in a monotonous manner. Also, despite the high cost of the device, it operates in a manner similar to that of a toy and thus it does not sufficiently satisfy human visual sensitivity.